(RICHMOND, Va.) – The North Anna and Upper Pamunkey Branches, including Terry’s Run, of Lake Anna in Orange, Louisa and Spotsylvania counties are continuing to experience a harmful algae bloom (HAB).
The Virginia Department of Health (VDH) advises the public to avoid contact with the lake in this area until algae concentrations return to acceptable levels. Some harmful algae, called cyanobacteria, can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea. The area to avoid can be seen on an interactive map at the Algal Bloom Surveillance Map. A status report containing the updated advisory areas may be viewed at Lake Anna Status Report 9.17.21.
Samples results from collections on September 9 indicated that at seven locations in the North Anna and Pamunkey Branches, swimming advisories continue to be necessary due to unsafe levels of potential toxin producing cyanobacteria. People and pets are advised to avoid swimming, windsurfing and stand-up paddleboarding, as well as other activities that pose a risk of ingesting water.
The samples collected downstream at the confluence of the two branches, at the Lake Anna State Park beach and at the Route 208 bridge, indicated cyanobacteria densities were at acceptable levels and do not necessitate a swimming advisory. Cyanotoxins were detected at each of these sites, but were well below safe swimming levels.
Follow-up monitoring above Route 208 on the lake is planned (weather permitting) the second week of October and will be the final round of follow-up sampling conducted in 2021 for Lake Anna.
The sections of the lake currently under advisory (no change in advisory extents compared to August):
North Anna Branch
Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. Most algae species are harmless, however, some species may produce irritating compounds or toxins. Avoid discolored water or scums that are green or bluish-green because they are more likely to contain toxins.
To prevent illness, people should:
WHEN IN DOUBT, STAY OUT!
VDH and the Virginia Harmful Algal Bloom Task Force, which includes the VDH, the Virginia Department of Environmental Quality, and the Old Dominion University Phytoplankton Laboratory, will continue to monitor water quality in the lake. In general, advisories will be lifted following two consecutive test results with acceptable levels for algal cell counts and/or toxin concentration. An advisory may be lifted or maintained at the discretion of the health department. For example, after one test an advisory may be lifted if results are within safe levels for swimming if other information indicates exposure or human health risk is low.
For more information visit www.SwimHealthyVA.com.